1. Field of the Invention
The present invention relates to the field of production of in vivo medicine carriers. More particularly the present invention relates to the field of large scale production of in vivo medicine carriers for intravenous or other routes (e.g., subcutaneous, intra-peritoneal, epidural or spinal) of drug administration.
2. Description of the Prior Art
Many manufacturing processes require the addition of components in a well defined sequence and controlled condition. Some critical steps may require instantaneous mixing of certain components to achieve uniformity of product properties.
For example, in the synthesis of spherical particles in a suspension medium, the instantaneous mixing of immiscible, semi-immiscible, or even completely miscible material before further stabilization will determine if the particles become homogeneous in size and remain stable as monodispersed particles.
Another example will be the production of aerosol particles from more than two gaseous components, any two of which can react to form a solid particle. However, a well defined ratio of more than two components are desired within the final product, thereby requiring instantaneous contact of all the components within a small three dimensional space and within a very limited time allowance.
Such stringent requirements may be met if the reaction vessel is small in size so that all of the components can be introduced accurately in time and in the right amount and to achieve instantaneous mixing (e.g., in milli- or microseconds.) However, proportional enlargement of the same reaction vessel to achieve large scale production will not guarantee uniform mixing within the desired short time span.
The existing art mostly consists of vessels with a motorized blending blade to achieve quick mixing of components. Even so, the mixing may still not be quick enough. In addition, the large shearing force created by such mechanism may be destructive to the materials involved, or create unwanted air bubbles.
The entire process may also require sequential addition of multiple components. Variability in each step will compound the quality control problem. For example, suppose the first step requires the mixing of component A with component B to result in the first intermediate component C. Assume further that due to poor mixing this step took two seconds to complete. Within these two seconds, some component A came into contact with component B within the first microsecond and started to grow in size, while other component A did not come into contact with component B until the last microsecond before the two seconds elapsed.
Therefore the result is to end up with a range of large and small C particles to start with after the two seconds. If one then wanted to add a color by mixing in component D and could not control the mixing condition then one would have a range of darker and lighter particles of small to largo sizes. But one could not get, for example, all small particles to be lighter color, and all large particles to be darker in color. It is obvious that the quality of the product becomes drastically more difficult to control as the number of steps are increased.
It is highly desirable to have a method which is suitable for large scale production to obtain uniform and controlled sequential mixing within a short time.